Upgrade SSH on ReadyNas Duo v1 to openssh-portable_9.8.1-1_sparc

Hello,

I was able to switch to a newer OpenSSH version on my ReadyNAS Duo v1.

I created a migration guide here: https://github.com/mfe-/ReadyNASDuoSparc/blob/master/openssh-portable_9.8.1-1_sparc.md If I should update my description of the guideline, let me know.

Disclaimer: You should have some basic Linux skills and make a backup of your NAS. If you don't know what you are doing, you can brick your device.

PS: My original user is mfe-. For some reasons I had to enter a new user name.